1. Field of the Invention
The present invention relates to methods and apparatus for shaking and harvesting fruit such as grapes or the like from rows of plants.
2. Description of the Prior Art
Assignee's tests with the harvesters described in the above referred to applications indicate that different varieties of grapes have different vine shaking characteristics for maximum removal of grapes with minimum damage to the grapes and vines.
In an attempt to provide a harvester that will economically harvest different types of grapes, certain prior art harvesters are provided with two totally different shaking heads such as a pair of vine shaking heads or a pair of trunk shaking heads with or without several vine strikers attached thereto. The present attempts to solve the above mentioned problem require that heavy and expensive heads be changed to harvest grapes from plant varieties having different dislodgment characteristics. In order to change the prior art heads, the harvesters must be transported to maintenance facilities, and in many cases require change-over times of about one day. Also, the phase, frequency, and acceleration relationships between the different elements of the prior art shaking heads cannot be easily changed during operation.
U.S. Tennes et al U.S. Pat. No. 4,208,861 which issued on June 24, 1980 discloses a trunk shaker which uses heavy free-swinging pendulums which absorb the reaction energy generated by reciprocating crank means when shaking the trunk, whereas the subject shaker relies on forcebalanced shakers for shaking fruit from vines.
U.S. Horn et al U.S. Pat. No. 4,250,700 which issued on Feb. 17, 1981 discloses a combination trunk and foilage shaker which requires a heavy mass to absorb reaction forces when reciprocating the trunk shakers.